Search for soft X-ray flashes at the fireball phase of classical/recurrent novae using MAXI/GSC dataSearch for soft X-ray flashes at the fireball phase of classical/recurrent novae using MAXI/GSC dataSearch for soft X-ray flashes at the fireball phase of classical/recurrent novae using MAXI/GSC dataSearch for soft X-ray flashes at the fireball phase of classical/recurrent novae using MAXI/GSC data